Invention of the Microchip
Written by Historian   
Thursday, 18 June 2020
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Invention of the Microchip
The Chip

All on one chip

Noyce should have come to the single chip solution earlier than he did, earlier than Kilby. After all his firm, Fairchild, was making transistors in the modern way - a large wafer subjected to diffusion on both sides to make a PNP or NPN structure. The wafer was  then chopped up, wires were connected to the slices and a can placed over each one. The idea of wiring up the transistors on the wafer should have occurred sooner but it took one other step forward.

 

hoerni

Jean Hoerni

Jean Hoerni, one of the other founders of Fairchild, came up with the idea of the planar transistor - a flat PNP junction insulated from the outside world by a layer of silicon dioxide.  The planar transistor was invented to overcome problems of contamination but Noyce started to think about the way that metal strips could be laid down on top of the insulating layer to connect separate planar transistors together. 

noycechip

Noyce's chip design was sophisticated

After inventing the connection method he then went on to think about resistors and capacitors and discovered that it was possible to put it all together on one piece of silicon. He was six months behind Kilby but his version of the idea was arguably more complete. He sketched the design of an adder built in on a single chip  - it would be a few years before the technology got that far. His concept of the integrated circuit is essentially one that would be recognised today and not at all like the slightly odd birds nest of wires of the Kilby version.

Legal wrangle

Although Kilby probably thought of the integrated circuit a bit before Noyce both Texas and Fairchild filed for patents and a long legal wrangle developed between the two.

One of the key points of contention was the use of flying interconnecting wires in the Kilby diagram - was this really a true integrated circuit? Kilby had realised the problem while the patent was being written and added some lines about being able to use any method of interconnection for instance gold tracks laid down on an insulating layer of silicon dioxide. Where this additional idea had sprung from is unknown but it certainly placed Kilby's chip alongside Noyce's in terms of sophistication.

The patent lawyers argued that Kilby's postscript wouldn't work because gold wouldn't stick to silicon dioxide and used experts to try to undermine Kilby's design. The patent was initially awarded to Kilby, or rather to Texas Instruments. Then the appeal judge, in 1966 roughly ten years on, reversed the decision and awarded the patent to Noyce, in other words to Fairchild.

Joint venture

By this time it didn't make any difference because the two firms had got together to carve up the market between them.

They each charged a royalty of between 2 to 4% which alone eventually earned them somewhere in the region of $100 million each. I say "eventually" because when both companies announced the technique in 1959 there were few takers. The reason was the high price of the relatively low component count chips that could be made. It was cheaper to build the same out of discrete components.

Surprisingly it wasn't the mainstream computer industry that initially created the market for integrated circuits. It was the combination of the space race and military electronics which needed the low weight and reliability of integrated circuits at any price. As the price fell and the number of components increased, a trend that continues today. First mainframe computers started to incorporate replacement printed circuit boards using chips in place of transistors and then whole integrated circuit computers were designed. Next came the minicomputer and then the microcomputer and we are still waiting to see where it will all end.

So what happened to Kilby and Noyce after the chip?

Irrespective of the outcome of the patent wrangle they are both generally credited as the co-inventor of the integrated circuit - both were awarded the National (USA) Medal of Science and inducted into the National Inventor's Hall of Fame.

Kilby stayed with TI for some time and his next important project for them was the design of the first pocket calculator. Kilby and his team first reverse engineered existing desktop calculators to see how they worked and then designed their own chips to do the same job. Along the way they also developed the first LED display and the first thermal printing mechanism. The result, the Data-Math sold for $149.50. Kilby was awarded the patent for the pocket calculator. He left TI in 1970 to work for himself as an independent inventor. Although he clocked up a number of patents none seem to have made him rich or any more famous.

In the mid 1960's Noyce was growing increasingly unhappy at Fairchild and he and Gordon Moore left to found Intel in 1986. The idea was make computer circuits on silicon and we know where that ended up don't we...

Perhaps the strangest twist to the story is that Noyce handed the task of designing the chips for a new desktop calculator for Busicom to an engineer by the name of Ted Hoff. He managed to cram the logic onto a single chip and so produced the world's first microprocessor. The trouble was that Busicom's machine was knocked out of the market place by Jack Kilby's cheaper pocket model and its subsequent clones.As a result Busicom couldn't pay Intel for the design work and so the rights to the chip returned to Intel who promptly placed it on open sale as the 4004 - the forerunner of the entire 80x86 line of processors.

Noyce moved ever more into management but always remained a techie at heart. Some of his financial decisions deserve recording, however. He warned his wife not to invest in a "no-future" company down the road at Cupertino, i.e. Apple, and then went and sank money into Osborne computers, which made the first portable, well luggable, machine and promptly went bust.

But the president of Intel could afford to make the occasional small mistake.

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